Self-cleaning well liner and the like



Nov. 3, 1936. F. E. FAIRFIELD 2,059,939

SELF CLEANING WELL LINER AND THE LIKE 7 Filed May 19, 1934 'INVENTOR BY %7 W 4 ATTORNEW Patented it. 3, 1936 v UNITED" STATES PATENT OFFICE Y snfir-cmsnmc WELL m snn'rnamxs rnmmn'mmgmcam.

mum m 19, m4, Serial No. 120.585 10laim. (0i.f16 6-5) This invention relates tooii well andparticularly'pertalns to self-cleaning liners,

'io'roilwellsandthelike.

V lntheoperationotoilwells,andothertypesoi s wells, it'is ottenthe practiceto provide aliner' whichkatubularmetalstructureadaptedto retain the well bore in proper form, and which r is formed with perforations through which fluid .irom the earthiormatlon being-penetrated may 10 low into the well. Incident to this operation the fluidswilltendtocarrysiltandotherearthy material through the perforations and will tend- 'to clog the same.="ihisis especially true due tothe common practice at the oi" 16 forming such perforations, which consists in cuttill! longltudinallyextending slot through the metal-wall by the use or a circular metal saw. 'The-remltoisuchacu tln operationisthat.

while sides of the slotted opening will be aOfparalle l and'straighigthe heri' formed by the cutting-tool at the ends of the slot will be inclined inwardly.. The'lower inclined iace presents aharrierwhichtendstocameanaccumulationoisilt and other finely divided material at the'bottom- 2 oithe'slot and tends to huildupthis mule, tion within the slot to clog the same. It isthe principalobiect or the present invention to provide a weIllinerandthelikestructure-withslotsf which prevent clogging, tend to insure'that theilowoifluid'throughtheslots-willmovethe 7 material which might otherwise accumulate therein, and slots'in airee'and unclogged condition throughout their length;

' 'll he present invention contemplates the tonna- 35 tion of slots through thewall-oi a' wel lj-liner or the like which is characteriaedby the'iact that at one ends thereof the'widthoi the slot f I is increased whereby ailuid will have re access to the slot and'will-ilow readily there invention is illustrated by wayoi example,

in drawln in which: i

- l lgure 1- is a view showing a Jinn o! a well iin'e'r'wltha seriaof slots formed I"ig. 2isanenlarged'viewinelevation showingapreierrediormotslotwithanenlarged opening at its lower 'end and indicating in dotted 50 lines the'portion oftheoriginal slot which'was removed.

1'18. 3'is a view in longitudinal section and elevation showing other detaih 'dthe Moon- 56 Ilg.'4isai'ngmontaryview-intransversesectionasseenonthe-lineL-lofFlg.2,andas showing the undercut sidewalls'oi the slot.

' Referring more particularly to the drawing. "indicates a tubular metal member, such for examples-s an oil well liner, the wall of which is 5 .iormed with perforations ll. As previously explained, these perforations are formed 7 the wall of the tubular member to permit gases,

yell, and other fluids to flow iromfthe earth.

formation into the well liner. It is common prac- 10 tice toiormthese membersinthe shapeoilongitudinal slots arranged in circumierentially extending rowsaround the liner and for any de sired length thereaions. slots are usually formed with parallel side walls I; and II, the

opposite endsoiwhichterminateininclined facesll, asegment oi the circumferential contour-.0! a cutting saw with which they are made. Such a iaceis shown in sectionin Fig.3

oi' thedrawing. Itismore desirable to form the and faces oi'the slots either square or Imdercut toward the inner face of the wall.. In common practieehowever, the machinework required to 1 thus perforate the liner is impracticable. The

side faces I! and" are, however, undercut, as

indicated by dotted lines in Fig. 2 0! the drawing,

and asmore particularlyshowninthe iragmentary section Figure 4. V The appearance of the lower end of the usual slotted perforation is indicated by dotted lines in Fig. 2 orthe drawing. In a slot of this character itwiilheseenthattheopeningsareuniiormin width throughout the length or the slot. and that- 'th'e'lower edge oithe slotis tapered downwardly and outwardly so that silt might accumulate upon it, and nnaiiycause a deposit of silt and other finely divided material from the well to in;the slot to completelyeor partially clog the same. Applicant contemplates changing the itfrmation of the slot'at one or both of its ends 40.

1 wherehytheendtaeeottheslotwmbestraight mjimight be undercut towardthe inside oi the Thisis preferably accomplished by drill-- liiiglah'ole ll atone orbothendsoith'eslohthe ashypunmandthatifdeslredtheenlarged he at another-shill thin-sub stantially circular as indicated in the drawing.

, In any event, however, the lower end of the slot slot and obstruct the passage therethrough.

It will also be evident that in the event'silt should become bridged across the restricted portion of the slot the eroding action of the fluid which passes through the relatively "wide portion I. of the slot at the lower end thereof, or at opposite ends thereof, as indicated in Fig. 1, at ID, will eventually wear away the bridged material and clear the slot. The result will be that the slots as here shown will be sell-cleaning at all times and will insure that the well liner may be maintained in its operative position without clogging and without retarding the amount of fluid going throughthe slot.

. It will thus be seen that the oil well liner and the like here disclosed, while decidedly simple in its construction, insures an operation which will maintain flow oi fluid through the wall of the liner without material obstruction, and will maintain the slots in a clear and clean condition.

While I have shown the preferred form of my invention, as now known to me, it will be understood that various changes may be made in the combination, construction, and arrangement of parts, by those skilled in the art, without departing from the spirit of the invention as claimed.

Having thus described my invention, what I ing straight side walls spaced apart a distance less than the diameter of the circular end openings, said straight side walls lying upon opposite (iivergent planes from the outside of the tubing toward the inside.

FREEMAN E. FAIRFIELD. 

